FR2520065A1 - DEVICE FOR CONTROLLING A HYDRAULIC ENGINE - Google Patents

Abstract

A DEVICE FOR CONTROLLING A HYDRAULIC MOTOR 2 INCLUDES A MEASURING STOPPER, IN PARTICULAR AN ELECTRO-HYDRAULIC PROPORTIONAL ACTION DISTRIBUTOR VALVE 1 AND AN ADJUSTING VALVE 7 AT THE BASIC POSITION OF A RELEASABLE NON-RETURN VALVE. THIS VALVE 7 INCLUDES A PISTON 20 HAVING A CONTROL SIZE X AND A SPRING 35 BEARING SUPPORT BETWEEN THIS PISTON AND A FIXED PART OF THE VALVE ENCLOSURE. VALVE 7 CONTAINS AN A2 CONNECTION POINT CONNECTED TO A B1 CONNECTION POINT OF THE MEASUREMENT SHUTTER. IT IS INTERCALED BETWEEN THE X CONTROL SIDE OF THE ADJUSTMENT VALVE AND THE OTHER A1 CONTROL POINT OF THE MEASUREMENT SHUTTER CONNECTED TO THE RECEIVER A FLOW REGULATOR 12 WHOSE CONTROL SIDE IS TURNED TOWARDS THE CONTROL SIDE OF THE ADJUSTMENT VALVE. THE CONTROL PANELS OF THE FLOW REGULATOR AND THE VALVE 7 ARE CONNECTED TOGETHER THROUGH A CHANGEL POINT 16 WITH A SUPPLY TANK 6.

Description

The present invention relates to a device for controlling a

  receiver, in particular, a hydraulic motor

  which includes a measuring shutter, in particular, a

  a proportional electro-hydraulic proportional distributor and an adjustment valve at the base of an unlockable check valve, said adjustment valve comprising a piston of

  control having a control side X, a control spring

  bearing between said piston and a fixed part of one envelope of the valve, and a connected connection point

  by another connection point, said measuring shutter.

  A known regulating valve, made in such a way as to

  stall a descent brake valve, is controlled directly

  by the pressure of a pump developing between this

  last and the hydraulic motor In the case of a fluctuating

  action of the pump pressure, the control piston of

  this down-braking valve is subject to fluctuating

  and the control of the descent brake valve is influenced by the same fluctuations. In these conditions, the connection to the

  down-valve and the valve coupling

  buenter connected to the reservoir of pressure differences which,

  for the same position of the control member of the valve dis-

  tributrice translates into different mean currents between

  the hydraulic motor and the feed tank (Perio-

  German dictionary "Fluid", February 1979, pages 31 to 33).

  In order to be able to control the independent hydraulic motor

  of its load, it is also known to interpose, between the control side of the brake and lowering valve and the hydraulic motor, a pressure control valve whose reduced constant pressure acts on the control piston

  of the brake valve In this way, the pressure exerted

  at the connection point at which the proportional valve is connected to the down-braking valve is kept constant, which allows, at the cost of a pressure loss in the ducts, to maintain the pressure difference between the connection connected to the valve of

  descent braking system and that connecting the valve

  In these conditions, fluctuations in

  pressure on the pump or receiver side no longer affect the amount of fluid returning to the tank.

  pressure balance, thus avoiding the need for

  However, the use of a pressure regulating valve is relatively complicated (DE-OS 29 11 891). The present invention aims to simplify

  considerably the structure of the last device mentioned.

  It achieves this purpose in that between the control side of the

  valve and the other connection point of the shutter

  a receiver connected to the receiver is inserted a flow regulator whose control side is turned towards the

  control of the regulating valve, in that the sides of the

  the flow regulator and the regulating valve are

  connected via a throttling point to a

  food service and that the space on the side

  the control piston is connected to the connection point

  adjustment valve connected to the measuring shutter.

  The method of construction according to the invention is sensitive-

  simpler than the one known, including a valve for

  pressure and, therefore, is more economical to

manufacture.

  Another feature of the invention is characterized in that a second adjustment valve is provided which, with a

  another connection point is connected to the measuring

  at the connecting points connected to the receiver, in that the connection point of the measured shutter of the first, adjustment valve is connected, via a

  flow regulator with the control side of a second valve

  of adjustment and in that between the connections connected to the closure

  the control valves of the two regulating valves and the respective flow regulator is interposed with a check valve.

  non-return opening towards the flow regulator cor-

  respondent, and one of which is open during operation,

while the other is closed.

  In another embodiment of the invention, characterized

  in that the two adjustment valves are housed in a housing

  so that their control elements can make opposite control movements, the arrangement is such that the control pistons are mounted with mutually opposed control sides, while each control piston has a control nozzle.

  measurement whose control edge controls a drilling of

  fixed and whose piston rod cooperates with the valve

  the main valve of the regulating valve, and that the nozzle

  and the main flap are closed, on one side of a disc

  positive when the main flap and the measuring nozzle are

  open on the other side and vice versa.

  Other features and advantages of the invention

  will emerge from the description which follows, with reference to

  attached drawing, in which Figure 1 is a block diagram of a device according to the invention; Figures 2A and 2B are longitudinal sections through a twin valve; and,

  FIG. 3 is a detailed view of a variant of FIG.

  of the twin valve of Figure 2.

  Distributor valve with multiple lanes or directions

  1 is constructed to form a proportional valve

  electro-hydraulic nature, which allows it, depending on a variable magnetic current, to determine the surface of

  restriction or throttling of the control spool and,

  the flow rate of the fluid under pressure The valve distributes

  this 1 has a connection Ai which, via a duct 3, is connected

  at connection A 3 of a regulating valve 7 leading to a

  normally closed non-return valve The connection B 3 of the valve

  7a is connected via a conduit 8a to a device

  of use such as a double acting hydraulic motor 2.

  A connector Bl of the dispensing valve 1 is connected, via a duct 4, to a connector A 2 of an adjustment valve 7 comprising

  also a normally closed non-return valve

  cord B 2 of the regulating valve 7 is connected, via a conduit 8,

  with the hydraulic motor 2 The dispensing valve 1 also includes

  a connection P which is connected to a pump 5 and another connection T which leads to a supply tank 6 A valve of s Oreté 27 prevents the pressure of the pump exceeds

a predetermined value.

  The regulating valve 7 has a control connection X which is connected via a duct 9 to a flow regulator 12 operating in the direction of the control connection X and the other side of which is connected via a control line. 14, to the conduit 3 to the control conduit 9 is connected another control conduit 15 which encloses a buse 16, preferably adjustable, which is connected by a conduit 17 to the reservoir 6 The nozzle 6 could be replaced by a limiting valve of

  pressure also acting as a choke point;

  The regulating valve 7 has a main member 19 and a control piston 20 actuated thereby, and opposite faces of equal cross sections can be

  subjected to the pressure of pressure from

  X and A 2 cords A spring 35 is interposed between the orien-

  to the connection X of the control piston 20 and a part

  fixed of the envelope of the regulating valve 7 The piston of com-

  20 comprises a rod 23 extending from the side facing towards

the main valve 19.

  In conduit 4 is connected a control conduit 14a, in

  which is interposed downstream of the connection point of the con-

  22, a non-return valve 26a followed by a flow regulator 12a, corresponding to the regulator 12, and towards which the valve 26 has opened A valve 26 opening towards the regulator of flow 12, is also interposed in the conduit 14, downstream of the connection point of the control conduit 22 which opens into the space containing

the piston rod 23.

  The construction of the regulating valve 7 associated with the

  flow limiter 12a and nonreturn valve 26a is similar

  to that of the regulating valve 7 associated with the regulator 12 and the valve 26.

  The corresponding conduits have been designated by the same references,

  we added the letter "a" to distinguish them.

  The control points X and Xa of the adjustment valves 7 and 7a and the control points of the flow regulators 12 and 12a are connected together and to the nozzle 16 via the conduits 9, 9a and 15 as shown in FIG. the drawing, the control ducts 9 and 9 respectively leading to the control points X and Xa and to the control side of the flow regulator 12 and 12a, while the duct 15 connects the control ducts 9 and 9a to the

nozzle 16.

  Assuming that the proportional action dispensing valve

  1 connects its connection P to the point AI and the point Bl to the T connection, this has the consequence that the pressure limiting valve 27 reduces the preset pressure by an amount corresponding to the flow resistance in the duct 3 and in the valve 19a of the regulating valve 7a, and that of circulation in the conduit 8a leading to the inlet of the hydraulic motor 2 On the side of the spring of the valve 19 of the regulating valve 7 exerts the pressure of the pump

  at connection B 2 of conduit 8a, increased or decreased by

  developed by the load of the hydraulic motor 2, according to the direction of action of the latter The flow regulator 12 passes, independently of the pressure in the duct 3, a constant average flow towards the control duct 9 Ce current at constant mean pressure develops, at the nozzle 16, a constant holding pressure which, through

  the connection X acts on the control piston 20.

  at coupling A 2 of the adjusting valve 7 remains

  constant This pressure corresponds to the pressure in the

  control cord X supplemented with the pressure resulting from the force of the spring 35 and subtracted from the pressure developed

by the compression spring 49.

  With the help of the regulating valve 7, the fall is maintained

  of pressure between the connections Bl and T of the distributive valve

  this with constant proportional action 1, so that, inde-

  while the pressure prevailing in the duct 8, a constant fluid flow through the dispensing valve 1 The excess pressure between the connections B 2 and A 2 is absorbed by the

main valve 19.

  The effect of the other adjusting valve 7a is the same as

  that of the valve 7 When, as shown, the valve dis-

  1 is in its central position, the connections AI and B1 are connected directly, and the X and Xa control connections through the nozzle 16, with the supply tank 6 In these conditions, the pressure at these connections corresponds to the pressure of the supply tank and the springs 49 and 49 has adjusting valves 7 and 7 closed the main valves 19 and 19 has against the pressure developed by the load in the hydraulic motor 2 As will be seen subsequently, in the other operating positions of the proportional proportional valve 1, the main valves 19 and 19 also isolate the pressure of the hydraulic fluid developed by the load when, as a result of the

  rupture of a pipe or a power failure, the pressure

  The advantage of the regulating valves 7 and 7a of the type described above resides in that they operate as pressure balances with respect to the pressures developed by the loads. irrespective of the direction of the charge in question.

  conditions, the runaway loads are effectively halted.

  In addition, the main valves 19 and 19a and their organs

  pre-order 51 and 5 ia (Figure 2) provide an

  circuits in the absence of pump pressure and

  thus prevent the descent of the load.

  Assuming that the hydraulic motor 2 consists of a differential cylinder with a ratio of the surfaces of 1/2 and admitting that the external load is exerted on the

  annular surface surrounding the piston rod, this results-

  in the case of a descent, in this cylinder room

  a pressure equal to the sum of twice the pressure of the pump and that developed by the load To prevent such pressure being exerted in the cylinder, one adopts

  for throttling surfaces 1 limited by the valve

  tributary 1 in the passages of Ai and Bl towards T a sec-

  greater than that of the throttling

  in the passages from P to Al and BI Thus, a load-independent setting is changed, in the case of a load

  in these conditions, the pressure

  pressure exerted on the side of the piston rod in the cylinder

  differential is approximately limited to the pressure

  The regulating valve 7 fills, in these

  conditions, the functions of a descent brake valve.

  As will be seen later, the use of two releasable valves 7 and 7a results in a simplification of the

  because the flow regulator 12 provides,

  7a, a constant average fluid flow to develop a constant throttling pressure at the nozzle 16 for the control fitting X of the regulating valve 7

  reciprocal is also true for the flow controller 12 a.

  In the embodiment shown in the figures

  2 A and 2 B, the valve comprises a casing 18 pierced with a hole

  central wise 31 in both ends of which are inserted a sleeve 32 and 32a The opposite sides of these bushings respectively have an end portion 33 or 33 a. The two end portions 33 and 33a are applied against each other and occupy the center of the bore 31 The sockets 32 and 32a are respectively held by a cylindrical hollow screw 34, 34a inserted in the The hollow screw 34 presses the sleeve 32, by means of its shoulder 30, on

  a counter-shoulder of the envelope 18, while the shoulder

  30a of the socket 32a is slightly spaced from the counter

  corresponding shoulder of the envelope 18.

  The control piston 20 is received in the region of the

  end portion 33 of the sleeve 32 A spring 35 is

  awarded between the end portion 33 and the control piston

  The control piston 20, which has a tubular shape, pre-

  at its periphery, a measuring nozzle 36 passing through

  ci.-In the position of the control piston 20 shown in the drawing, the sleeve 32 has, in the region of the measuring nozzle 36, a groove 37 between the groove 37 and the part

  end 33 the bushing 32 is pierced with a coupling orifice

  radial channel 38 which opens into a groove formed in the

  this outer of the bushing 32 In the position of the piston of

  control 20 shown in the drawing, the orifice 38 is free.

  The edge of the control piston 20 adjacent to this orifice 38

constitutes the control edge 40.

  In the rod 23 of the control piston 20, which is hollow,

  is screwed in the vicinity of the piston 20, a set screw 42.

  In addition, this rod is pierced in the vicinity of the piston of com-

  Mande 20, radial channels 43 which communicate the interior of the piston rod 23 with the space 44 which surrounds the rod

  piston 23 carries, at its end remote from the piston of com-

  20, an axial pin 45 parallel to which extends bores 82 parallel to the end face of the piston rod 23 The piston rod 23 is guided in a transverse wall 41 of the sleeve 32 which separates the space 44 and 46 The space 44 is connected, by means of a radial channel 47 formed in the sleeve 32, to the groove 48 surrounding the sleeve 32 In the radial channel 47, could be introduced a screw having a throttling point. On the opposite side to the end portion 33 of the sleeve 32 is slidably accommodated the main valve 19 which has a tubular shape A spring 49, compressed between the bottom of the hollow screw 34 and the valve 19, solicits the latter to Against a frustoconical seat 50 of the bushing 32 In the main valve 19 is located axially sliding a pre-control member 51 which has a frustoconical portion 52 and

  a part 53 in the form of a drawer The frustoconical portion 52 comprises

  requires a stepped bore 54 formed in the bottom of the valve 19, while

  part 53 has transverse channels 79 extending

  radially in the envelope of the valve 19 and which open outwards and inwards into grooves 55 and 56 of said

main valve 19.

  The pre-control member 51 has a central bore 57 extending to the portion 52 and into which may be introduced, on the opposite side to the portion 52, a screw having a throttling point The central bore-57 communicates, by a transverse channel 58 with a space 59 which is limited by the bottom of the main valve 19, the part 52 and the part of the pre-control member 51 facing said portion 52 The portion 53 of the valve has a throat 60 which, in the position shown of the pre-order member

  51, is disposed on the side of the groove 56 opposite the portion 52.

  The groove 60 communicates with holes 61 provided in the pre-control member 51, parallel to the main bore 57, and which open into the space 59 between the pre-control member 51 and a pierced washer 63, held by a circlip 62, is

  Compressed spring 64 The prestressing of this spring is such that

  when the main valve 19, 19 has acted as a non-return valve, the pre-control valve 52, 52 a

remains closed.

  The groove 48 is placed in front of a groove 80 of the enve-

  loppe 18 which is connected by a cavity 65 and a hole 66 with the connection point A 2 The space 46 communicates with

  the groove 48 by an oblique bore 67 In the position

  19 of the main valve 19, the groove 55 adjacent thereto has radial channels 68 which open into a

  the throat 69 of the envelope 18 The throat 69 communicates by means of a

  70 and a hole 71 with the connection point B 2.

  In a groove 37 formed in the region of the outer face

  the sleeve 32 is housed in a sealing ring 72.

  A second sealing ring 73 is interposed between the

  ge 48 and the radial bores 68 The rings 72 and 73 seal the gap between the sleeve 32 and

  the casing 18 Beside the radial bores 68, the opposite side

  end portion 33 has radial bores 74 whose diameter is smaller and which do not open, as the radial bores 68, in the groove 75 of the sleeve 32, but in the groove 69 of the envelope 18 The hollow screw 34 is applied against a sealing edge 83 of the sleeve 32. The gap between the screw 34 and the casing 18 is sealed by

  a ring 76 The end portion 33 has the same diameter ex-

  than the bottom of the groove 39 on the side of the socket 32

  turned towards the end portion 33.

  The components just described are located.

  in the right half of the envelope 18 The components.

  contained in the left side of the envelope 18 correspond

  to them and were essentially designated by the same

  numerical ferences to which we have added, for further clarification

letter, the letter "a".

  The envelope 18 has, in its central part, a point.

  C connecting the conduit 17 This point of

  connection has a bore 77 in which a screw

  terchangeable 78, receiving the nozzle 16, is screwed.

  When the connection point A 3 is connected, via the dispensing valve 1, to the pump 5, the pressurized fluid circulates through the opening 66 a, the cavity

  a, the groove 48a, the oblique bore 67a and the space 46a.

  Under the pressure of the fluid, the main valve 19a opens, thus permitting, by the radial bores 68a, the grooves a and 69a, and the cavity 70a and the bore 71a, the fluid under pressure to reach the connecting point B 3 and from there to gain through the conduit 8 to the hydraulic motor 2 The opening position of the main valve 19a is limited as soon as the edge limiting the groove 55a and which is turned towards the seat a , exceeds the radial bore 74a in the sleeve 32a and thus closes the space in which the springs 49a and 64a are housed At the same time, the pressurized fluid flows from the groove 48a through however, there is communication between the spaces 46a and 44a by the hollow piston rod 23.

  control piston? Oa opposite its rod is subject to the pressure

  sion of the fluid discharged by the pump 5 In the position

  of the control piston 20a, the space containing the

  control spring 35 is isolated from the space 44 a, but

  by the bore 38a, the groove 39a, the nozzle 16 and the

  77, as well as via the conduit 175 with the reservoir 6. The control piston 20a is displaced, together with the piston rod 30a, by the pressure prevailing in the chambers 44a and 46a, against the spring force 35, to the right, according to the figure, which has the effect of communicating the groove 37a with the space 44a by allowing the fluid under

  pressure to flow through the measuring nozzle 36 in the chamber.

  containing the control spring 35 a During the moving

  from the control spool 20 a towards the part of ex-

  tremity 33a, the control edge 40a of the piston 20a passes

  above the mouth close to the control opening 38a, thus reducing the section of this mouthpiece. As a result, it develops in the space containing the control spring 35.

  pressure which increases until, as a result of the equi-

  releasing forces acting on it, the control piston 20 has immobilized On the left side of the rod 23a of the control piston 20a acts the pressure prevailing in the chambers 44a, 46a, while on the right side , according to the drawing, of the piston

  control 20 a acts the pressure prevailing in the space containing

  the spring 35a and the force of this spring 35 has

  Even between the space 44a and the space containing the spring 35a, there is a pressure difference corresponding to the force of the control spring 35a In the equilibrium position of the piston 20a, a constant amount of fluid crosses the measuring nozzle 36a, the control bore 38a and the nozzle 16 (throat) to the reservoir 6 which corresponds to the section of the measuring nozzle 36a and to the pressure corresponding to the

spring force 35 a.

  The pressure that develops in the two connected throats

  39 a and 39 is determined by the section Strangling 16.

  The pressure in the grooves 39a and 39 is propagated through the control hole 38 to the space containing the spring 35 and acts in the same direction as the spring on the piston.

  control located in the right half of the envelope 18.

  This pressure remains constant as long as the control piston

  35 a is in its equilibrium position.

  The pressure exerted on the side of the end

  33 on the control piston 20 and the resultant force a

  firstly, to lift part 52 of the

  51 of its seat in the main valve 19,

  The drawer-shaped portion 53 intersects the communication between the connector B 2 and the chamber containing the valve spring 49. The pressure generated by the load acting on the hydraulic motor 2 in the chamber containing the spring 49 collides with the central bore 57, the transverse bore 58, the chamber 59, the stepped bore 54, the pressure of the chamber 46 or 44 Thus, the main valve 19 is exposed to equal pressures and the control piston 20 is applied by its piston rod 23, against the main valve 19 and

  lift it from the frustoconical seat 50 of the sleeve 32 Main-

  holding, the main valve 19 is moved by the piston 20, against the force of the spring 49, until a certain pressure has developed in the fluid flowing through the connection point B 2, drilling 71, the cavity 70, the two grooves 69 and 75, the radial channels 68, the chamber 46, the oblique bore 67, the two grooves 48 and 80, the cavity 65,

  the piercing 66 and the connection point A 2, at the edge of the

  proportional valve dispenser valve 1.

  This pressure, which acts by the radial holes 47 in the space 44 and on the annular surface of the control pistion, as well as, by the transverse holes 43 and the holes 82 parallel to the pin 45, on the surface of the rod piston 23 opposes, together with the force of the spring 49, the force of the control spring 35, and the pressure in the space in which the spring is housed. The forces acting on the control piston 20 are balanced when the sum of the forces of the control spring 35 and the pressure in the chamber containing said spring

  35 is, on the one hand, equal to the sum of the

  sion in the space 44 on the piston rod 20 and the force exerted on the piston rod 23, in addition, by the force of the spring 49, on the other hand Since the force

  exerted from the left, according to the drawing, on the

  control tone 20 is constant, resulting in the development of

  in Chamber 44 and thus at the point of connection

  A 2, of constant pressure.

* on the hydraulic motor varies, it results

  the previous constant pressure at connection point A 2 by corresponding adjustment movements.

main valve 19.

  Operation on both sides of this double valve

  reverses when the sides of the hydraulic motor are

  2 respectively connected to the discharge of the pump 5 and

to the supply tank 6.

  The desired constant control pressure necessary to obtain a load independent braking motion is not obtained in the double valve described above, by an auxiliary control device, but simply by the control piston 20a or 20 on the side of the double valve whose main valve 19 has or 19 controls the supply of fluid under pressure of the hydraulic motor 2 This results in a compact construction mode which is further favored by

  the fact that in the double valve shown, the space

  the two control springs 35 and 35 are facing each other.

  and are connected by the grooves 39 and 39a to a common nozzle 16.

  Since the same pressure prevails in the chambers

  holding the control springs 35 and 35a, no special switching element is required between these two chambers. It can therefore be seen that the control pistons 20, 20 a also fulfill the function of a flow regulator by means of which the two adjustment valves 7 and 7 are housed in an envelope

common 18 can cooperate.

  In FIG. 3, in place of the nozzle 16, in the bore 77, a pressure limiting valve 83 is used which opens towards the channel 81 connected to the control duct 17. In the piercing 77 has been introduced From the outside, a set screw 84 On the opposite side to the screw 84, the bore 77 has a narrowing having substantially no throttling effect which is connected to the groove 39 The opposite side to the throat 39 of this tightening point constitutes a seat which cooperates with a conical shutter 85 between the screw 84 and

  the shutter 85 is compressed a spring 86.

  It should be noted that the term "throttling point"

  tends to designate the nozzle 16 as the limiting valve

pressure 83.

  Of course, the invention is not limited to the embodiment which has just been described and shown. It will be possible to make numerous modifications to detail, without leaving

for that the Ladre of the invention.

R E VE NOI CA TIO N S

  Control device for controlling a receiver,

  in particular, a hydraulic motor (2) which comprises an ob-

  measuring device, in particular an electro-hydraulic proportional valve (1) and an adjusting valve (7) at the base of an unlockable check valve, said control valve comprising a control piston ( 20) having a control side (X), a control spring (35)

  appu-i between said piston and a fixed part of the enve-

  valve port, and a connection point (A 2) connected by another connection point (RI) to said measuring shutter, characterized in that between the control side (X) of the control valve and the Another connection point (A 2) of the measuring shutter connected to the receiver is interposed with a flow regulator whose control side is turned towards the control side of the control valve, in that the control sides of the flow regulator and the valve

  setting are connected via a choke point

  16,83) to a supply tank (6) and that the space (44) on the control side of the control piston is connected to the connection point (A 2) of the control valve

connected to the measuring shutter.

  Control device according to claim 1, characterized in that a second adjusting valve (7a) is

  which with another connection point (AI) is

  linked to the measuring shutter (1) and to the connection points

  (A 3, B 3) connected to the receiver (2), in that the connection point

  of the measuring shutter (1) of the first regulating valve is connected via a regulator of

  flow rate (12a) with the control side of a second control valve

  (7) and that between the connections (A 2, A 3) connected to the control shutter (1) of the two adjustment values and the respective flow regulator is interposed

  a non-return valve (26,26 a) opening towards the

  flow regulator and one of which is open during

  the operation, while the other is closed.

* 16 2520065

  3 Device according to claim 2, characterized

  in that the control sides (X, Xa) of the control pistons

  (20, 20 a) and the flow regulator (12, 12 a) are connected together. 4. Device according to any one of the preceding claims, characterized in that the two adjustment valves (7.7 a ) are housed in a common casing (18) so that their control elements can perform opposite control movements, the arrangement being such that the control pistons (20,20 a) are mounted with sides of mutually opposed control, while each control piston has a measuring nozzle (36, 36 a)

  whose control edge (40, 40a) controls a drilling of

  stationary (38.38 a) and whose piston rod cooperates with the main valve (19, 19 a) of its control valve (7.7 a) and in that the measuring nozzle (36) and the flap (19) are closed on one side of the dispenser when the main valve (19a) and the measuring nozzle (36a) are open on the other side.

and vice versa.

  Device according to claim 4, characterized in that the main valve (19) comprises a chamber for receiving a control spring (64) which communicates, at least by a transverse bore (79) of the main valve with a groove (69). connected to the receiver, and that this link is

  interrupted in a predetermined position of the main valve.

  Device according to claim 4 or 5, and in

  which the main valve (19, 19a) contains an organ of

  control (51, 51 a), characterized in that said main valve has a control opening (56, 56 a) in that the pre-control member has a drawer-like portion (53, 53 a) cooperating with this control opening and in that said

  control opening is connected to the transverse bore (79).

  Device according to any one of the claims

  4, 5 or 6, characterized in that the main valve (19, 19a) and the control piston (20, 20a) are housed in a sleeve (32, 32a) inserted into the casing (18) which sleeve has a control passage (38, 38 a) which can be controlled by the piston, in that the control bore opens into a groove (39, 39 a) arranged along the periphery and which is connected with the groove ( 39a, 39) limited by the other bushing, these two grooves being connected together via the nozzle

(16) with the reservoir (6).